@Article{ 
  ste03,
  author = { Stepanov, Eugene },
  title = { Representation of atomic operators and extension problems },
  journal = { Proc. Edunburgh Math. Soc. },
  year = { 2004 },
  volume = { 47 },
  pages = { 695-707 },
  URL = { http://cvgmt.sns.it/paper/312/ },
  note = { cvgmt preprint}
}